Double-sided adhesive tape and method for fixing a sealing element in place

ABSTRACT

The invention relates to a double-sided adhesive tape ( 24 ) and a method for fixing a sealing element ( 10 ) in place, preferably in motor vehicles, comprising a sealing body ( 12 ) made from silicone, to which a first self-adhesive sticking surface ( 18 ) of a double-sided adhesive tape ( 24 ) is applied at least partly comprising a silicone glue. The double-sided adhesive tape ( 24 ) is provided with a second self-adhesive sticking surface ( 20 ) for fixing to the site of application.

[0001] This invention relates to a double-sided adhesive tape and a process for attaching a sealing element which comprises a sealing body, consisting of silicone, to an application site using silicon cement.

[0002] In the motor vehicle domain there are silicone seals which are provided with an insertion foot, by means of which they can be inserted at the application site. This type of attachment however entails high production demand and high demand for installation space and is disadvantageous in this respect.

[0003] German patent application DE 199 52 399 which was not published beforehand furthermore discloses a silicone seal which can be attached by means of a liquid silicone cement to an adhesive tape which acts on one side; its outer adhesive surface which is initially covered by a protective film is used for attachment at an application site after the protective film is removed. The several hours of setting time of the liquid silicone cement makes process-reliable use difficult in mass production designed for rapid throughput. Another disadvantage of this silicone seal is that by using liquid silicone cement a soft-elastic connection between the carrier element and the sealing body of the sealing element takes place, since liquid silicone cements as permanently sticky cements lead to a reversible adhesive connection which under certain stress conditions leads to an adverse effect on sealing action, for example when used in sliding motor vehicle roofs.

[0004] Due to the soft-elastic connection, displacement as far as detachment of the sealing body can take place so that undisturbed operation of a sliding motor vehicle roof is not guaranteed.

[0005] DE-G 94 17 149 discloses a sealing element with a sealing body of elastic material which has an adhesive surface, by means of which it is attached to the bottom of the cover of a sliding roof, lifting roof, etc. The adhesive surface is made on an adhesive tape which is attached with its back to a base body which is connected to the sealing body and consists of a stiffer material than the sealing body. Before attachment of the seal the adhesive surface is protected with a removable protective film.

[0006] Other sealing elements are known from DE 197 20 713 C1 and EP 0 357 973 B1, the preferred material for the sealing body being ethylene-propylene rubber (EPDM). This material is however not optimally suited with respect to its temperature resistance, restoration behavior, sealing properties, and danger of freezing-on and conglutination.

[0007] The object of this invention is to devise a double-sided adhesive tape and a process for producing and for attaching a sealing element with the sealing body, consisting of silicone, to an application site, by means of which economical production of a quick and simplified as well as process-reliable adhesive connection at the application site is enabled.

[0008] This object is achieved as claimed in the invention with respect to the double-sided adhesive tape by the features of claim 1, with respect to the process for attachment by the features of claim 7, and with respect to the process for production by the features of claims 17 and 18. One advantageous use of the subject matter and the process is given in claim 19. Advantageous embodiments of the invention can be found in the dependent claims.

[0009] The double-sided adhesive tape with one adhesive surface which has a silicone cement enables for the first time the simple, prompt and reliable possibility of attachment of one such adhesive tape to an opposing surface of silicone.

[0010] Another advantage is that the silicone cement placed between the carrier element and the sealing body enables a material and frictional connection which is formed by crosslinking and full curing of this silicone cement.

[0011] Preferably the component areas of the first adhesive surface can be provided with a quick-setting cement, for example an acrylate cement, which when the first adhesive surface is applied to the opposing surface of silicone provides first of all for tentative fixing, while the silicone cement in the other areas cross links or fully cures to produce operating strength.

[0012] Alteratively, the first adhesive surface can also contain a mixture of silicone cement and another adhesive, such as for example acrylate cement.

[0013] Because in the process as claimed in the invention for attachment of the sealing element to the sealing body initially a first adhesive surface of a double-sided adhesive tape, which surface has a silicone cement, is applied, the sealing element is prepared such that after pulling off the protective film with its second self-sticking adhesive surface with an adhesive which is preferably matched to the properties of the corresponding application site, the sealing element can be attached easily and quickly to the application site, for example to one edge of a sliding roof cover or an opening edge which surrounds the latter.

[0014] In the approach as claimed in the invention, it is advantageous for the sealing body consisting of a silicone to have outstanding properties with respect to temperature resistance, restoration behavior, tightness and protection against freezing-on and conglutination and still the sealing element can be attached quickly, easily and with little demand for installation space to the application site, while for example with direct cementing of the sealing body to the application site by means of silicone cement as a result of the resulting long setting time, use in series production is not possible.

[0015] The invention overcomes a prejudgment of the specialty according to which the advantages of a silicone seal cannot be combined with simple installation using a self-sticking adhesive surface which is provided on the seal. By using a cross-linking or fully curing silicone cement it is surprisingly possible to produce a material and frictional connection between the sealing body and the double-sided adhesive tape and the application site which does not have any soft-elastic properties and likewise does not necessitate additional setting times.

[0016] In one preferred embodiment of the invention the second adhesive surface is formed for example by an acrylate cement. The carrier element is especially preferably formed from an acrylate foam which contains an acrylate cement and thus itself directly forms the second adhesive surface facing the application site. Furthermore, the adhesive surface is preferably made planar.

[0017] Between the first and second adhesive surface of the double-sided adhesive tape there is a carrier element which is formed preferably by a flexible tape. The adhesive surface extends preferably essentially over the entire length of the sealing body. According to one alternative embodiment the carrier element is formed by an acrylate foam.

[0018] Production of a sealing element as claimed in the invention which has a sealing body consisting of silicone is done by continuously producing the sealing body consisting of silicone by an extrusion process in a first process step and by at least partially coating the double-side adhesive tape with a silicone cement in a second process step.

[0019] In a third process step the sealing body and the double-sided adhesive tape are joined to one another via the silicone cement which forms the first adhesive surface and in a fourth process step the silicone cement which forms the adhesive surface is crosslinked by the action of temperature and/or pressure and/or moisture.

[0020] This process as claimed in the invention makes it possible to control, by monitoring, the time of cross-linking or full curing of the silicone cement which forms the adhesive surface via the parameters of temperature and pressure, so that the sealing element as claimed in the invention in the attachment to the application site always has material and frictional engagement between the sealing body and the double-sided adhesive tape.

[0021] Another process as claimed in the invention for producing the sealing element is characterized by a first process step in which the sealing body consisting of silicone is continuously produced by the extrusion process and in which in a second process step a silicone cement is at least partially applied to the planar bottom of the sealing body.

[0022] In another process step, the double-sided adhesive tape is joined to the sealing body which has the silicone cement and in a fourth process step crosslinking of the silicone cement which forms the first adhesive surface is implemented by the action of temperature and pressure.

[0023] When using a carrier element of acrylate foam, between the adhesive surface of silicone cement facing the sealing element and the carrier element a primer is applied in an intermediate step.

[0024] It was furthermore advantageously ascertained that by the controlled action of moisture on the silicone cement which is to be crosslinked and which forms the first adhesive surface another influencing parameter arises which benefits the material and frictional engagement between the sealing body and the double-sided adhesive tape.

[0025] One embodiment of the invention is detailed by way of example below.

[0026]FIG. 1 shows a schematic perspective of a motor vehicle roof with an openable cover,

[0027]FIG. 2 shows a cross section through a sealing element which is to be attached to the cover edge,

[0028]FIG. 3 shows a cross section through a sealing element which is located on the roof frame,

[0029]FIG. 4 shows a cross section through an alternative structure of a double-sided adhesive tape with an acrylate foam as the carrier element.

[0030]FIG. 1 shows an openable motor vehicle roof 1 in which a roof opening 2 can be alternately closed or at least partially cleared by means of a cover 3. For sealing between the cover 3 with an outside edge labelled 26 in FIG. 2, and the edge 17 of the roof opening 2 there is either a seal 8 on the outer side 26 of the cover 3, as shown in FIG. 2, or a seal 5 on the edge 17 of the roof opening 2.

[0031]FIG. 2 shows a sealing element 10 which can be used for example as a seal 5 or seal 8 as shown in FIG. 1. The sealing element 10 is formed by a sealing body 12 which preferably consists of an elongated extrusion profile of silicone and a hollow chamber 16 formed on this extrusion profile. The sealing body 12 is made planar on its bottom over the entire length and width.

[0032] A double-sided adhesive tape 24 with a first adhesive surface 18 is attached to the sealing element 10; this surface is characterized in that it has a silicone cement which as a result of the small layer thickness and crosslinking forms a strong bond with the bottom of the sealing body 12.

[0033] One such double-sided adhesive tape 24 however is also outstandingly well suited for use at other application sites at which the positive properties of silicone take effect directly. In particular, in this connection seals on or in buildings are also conceivable.

[0034] The double-sided adhesive tape 24 comprises a flexible carrier element 14 which is joined to the first adhesive surface 18. The carrier element 14 is cemented by material and frictional engagement by means of the adhesive surface 18 of silicone cement over the entire length and width on the bottom of the sealing body 12. On the side of the carrier element 14 facing away from the sealing body 12 the double-sided adhesive tape 24 is provided with a second self-sticking adhesive surface 20 which is used for attaching the sealing element 10 to the application site.

[0035] The adhesive surface 20 is protected before attachment of the sealing element 10 to the application site by a protective film 22 which is then removed during installation. The removal of the protective film 22 is indicated by the arrow A and the subsequent joining of the sealing element 10 via the double-sided adhesive tape 24 is indicated by the arrow B. The material of the adhesive surface 20 is chosen depending on the adhesive base at the application site, preferably an acrylate cement being used. The adhesive surface 20 extends preferably over the entire length and width of the bottom of the double-sided adhesive tape 24 and is made essentially planar.

[0036] The described sealing element 10 is used preferably to seal the cover 3 of an openable motor vehicle roof 1, such as for example a sliding roof, lifting roof, sliding/lifting roof, louvered roof or spoiler roof, and it can be attached for example as a seal 8 to the side edge 26 or also on the bottom of the cover 3 or as a seal 5 to one opening edge 17 of a roof opening 2 which can be closed by the cover 3.

[0037] Finally, as shown in FIG. 3, attachment to a horizontal flange area of a roof frame 28 is also possible. In this case the cover 3 in the closed state from overhead adjoins the sealing element 10 to form a seal. The guide rail which is used to guide the raising and displacement mechanism of the cover 3 which is not shown is labelled 30.

[0038] In the version shown in FIG. 4, a carrier element 14 of acrylate foam is used; it is applied to a protective film 22. The acrylate foam contains an acrylate cement so that the bottom of the carrier element 14 after detachment of the protective film can be applied directly as an adhesive surface 22 to the application site. A primer layer 32 which is used to impart adhesion between the carrier element 14 and the adhesive surface 18 of silicone cement is applied to the top of the carrier element 14 which is formed from acrylate foam.

[0039] For example, material E 415 from Wacker Chemie is well suited as the silicone cement for producing the adhesive surface 18. The primer for producing the primer layer 32 is for example material G 718 from Wacker Chemie. The material acrylic foam from 3M is very well suited as the acrylate foam with the integrated acrylate adhesive surface.

[0040] This invention devises a sealing element which has good properties with respect to temperature resistance, restoration behavior, sealing properties, freezing-on and conglutination danger and still can be attached to the application site easily and promptly, in which neither plug connections which require relatively large installation space and installation effort, nor liquid silicone cement which entails a long setting time and which leads to a soft-elastic and thus reversible adhesive connection are used. Reference number list 1 motor vehicle roof 2 roof opening 3 cover 5 (vehicle-side) seal 8 (cover-side) seal 10 sealing element 12 sealing body (profile) 14 carrier element 16 hollow chamber 17 opening edge (of 2) 18 first adhesive surface (of silicone cement) 20 second adhesive surface 22 protective film 24 double-sided adhesive tape 26 side edge (of 3) 28 roof frame 30 guide rail 32 primer 

1. Double-sided adhesive tape (24) for attachment of a sealing element (10) to an application site, with a carrier element (14) which is located between two self-sticking adhesive surfaces (18, 20), characterized in that the sealing element (10) consists of a silicone material and the adhesive surface (18) facing the sealing element (10) is formed at least partially by a silicone cement.
 2. Double-sided adhesive tape as claimed in claim 1, wherein the silicone cement is a cross-linking silicone cement.
 3. Double-sided adhesive tape as claimed in claim 1 or 2, wherein the adhesive surface (18) which has the silicone cement has partial areas with another cement.
 4. Double-sided adhesive tape as claimed in one of the preceding claims, wherein the carrier element (14) is formed by an acrylate foam.
 5. Double-sided adhesive tape as claimed in claim 4, wherein the acrylate foam of the carrier element (14) forms the second adhesive surface (20) facing the application site.
 6. Double-sided adhesive tape as claimed in one of the preceding claims, wherein there is a primer (32) between the adhesive surface (18) which has the silicone cement and the carrier element (14).
 7. Process for attaching a sealing element (10) for use in motor vehicles, which comprises a sealing body (12) consisting of silicone, wherein the sealing element (10) which has a sealing body (12) with a first adhesive surface (18) of a double-sided adhesive tape (24), which surface has a silicone cement, after removing a protective film (22) with a second self-sticking adhesive surface (20) of the double-sided adhesive tape (24) is attached to the application site.
 8. Process as claimed in claim 7, wherein the second adhesive surface (20) is formed by an acrylate cement.
 9. Process as claimed in one of the preceding claims, wherein the double-sided adhesive tape (24) between the self-sticking adhesive surfaces (18, 20) is provided with a carrier element (14).
 10. Process as claimed in claim 9, wherein the carrier element (14) is formed by a flexible tape consisting of an acrylate foam.
 11. Process as claimed in one of the preceding claims, wherein the silicone cement forming the adhesive surface (18) is crosslinked with the sealing body (12) and the carrier element (14).
 12. Process as claimed in claim 11, wherein the silicone cement forming the adhesive surface (18) crosslinks by the action of temperature and/or pressure.
 13. Process as claimed in claim 11, wherein the silicone cement which forms the adhesive surface (18) crosslinks by the action of moisture.
 14. Process as claimed in one of the preceding claims, wherein the adhesive surface (20) extends essentially over the entire length of the sealing body (12).
 15. Process as claimed in one of the preceding claims, wherein the adhesive surface (20) is made essentially planar.
 16. Process as claimed in one of claims 10 to 15, wherein the second adhesive surface (20) is formed directly by the acrylate foam of the carrier element (14).
 17. Process for producing a sealing element for use in motor vehicles which comprises a sealing body (12) consisting of silicone, characterized by the following process steps: a) extrusion of the sealing body (12), b) application of the silicone cement which forms the adhesive surface (18) to the double-sided adhesive tape (24), c) joining of the sealing body (12) to the adhesive surface (18) of the double-sided adhesive tape (24), d) crosslinking of the silicone cement which forms the adhesive surface (18) by the action of temperature and pressure.
 18. Process for producing a sealing element for use in motor vehicles, which comprises a sealing body (12) consisting of silicone, characterized by the following process steps: a) extrusion of the sealing body (12), b) production of a carrier element (14) from acrylate foam with a protective film (22) on the bottom, c) application of a primer (32) to the top of the carrier element (14), d) application of the silicone cement which forms the adhesive surface (18) to the primer (32), e) joining of the sealing body (12) to the adhesive surface (18), f) crosslinking of the silicone cement which forms the adhesive surface (18) by the action of temperature and/or pressure and/or moisture.
 19. Use of a sealing element (10) as claimed in one of claims 1 to 6 for sealing attachment to an openable motor vehicle roof. 